| // Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| import 'dart:async'; |
| import 'dart:io'; |
| |
| import '../file_watcher.dart'; |
| import '../resubscribable.dart'; |
| import '../utils.dart'; |
| import '../watch_event.dart'; |
| |
| /// Uses the native file system notifications to watch for filesystem events. |
| /// |
| /// Single-file notifications are much simpler than those for multiple files, so |
| /// this doesn't need to be split out into multiple OS-specific classes. |
| class NativeFileWatcher extends ResubscribableWatcher implements FileWatcher { |
| NativeFileWatcher(String path) : super(path, () => _NativeFileWatcher(path)); |
| } |
| |
| class _NativeFileWatcher implements FileWatcher, ManuallyClosedWatcher { |
| @override |
| final String path; |
| |
| @override |
| Stream<WatchEvent> get events => _eventsController.stream; |
| final _eventsController = StreamController<WatchEvent>.broadcast(); |
| |
| @override |
| bool get isReady => _readyCompleter.isCompleted; |
| |
| @override |
| Future get ready => _readyCompleter.future; |
| final _readyCompleter = Completer(); |
| |
| StreamSubscription _subscription; |
| |
| _NativeFileWatcher(this.path) { |
| _listen(); |
| |
| // We don't need to do any initial set-up, so we're ready immediately after |
| // being listened to. |
| _readyCompleter.complete(); |
| } |
| |
| void _listen() { |
| // Batch the events together so that we can dedup them. |
| _subscription = File(path) |
| .watch() |
| .transform(BatchedStreamTransformer<FileSystemEvent>()) |
| .listen(_onBatch, onError: _eventsController.addError, onDone: _onDone); |
| } |
| |
| void _onBatch(List<FileSystemEvent> batch) { |
| if (batch.any((event) => event.type == FileSystemEvent.delete)) { |
| // If the file is deleted, the underlying stream will close. We handle |
| // emitting our own REMOVE event in [_onDone]. |
| return; |
| } |
| |
| _eventsController.add(WatchEvent(ChangeType.MODIFY, path)); |
| } |
| |
| void _onDone() async { |
| var fileExists = await File(path).exists(); |
| |
| // Check for this after checking whether the file exists because it's |
| // possible that [close] was called between [File.exists] being called and |
| // it completing. |
| if (_eventsController.isClosed) return; |
| |
| if (fileExists) { |
| // If the file exists now, it was probably removed and quickly replaced; |
| // this can happen for example when another file is moved on top of it. |
| // Re-subscribe and report a modify event. |
| _eventsController.add(WatchEvent(ChangeType.MODIFY, path)); |
| _listen(); |
| } else { |
| _eventsController.add(WatchEvent(ChangeType.REMOVE, path)); |
| close(); |
| } |
| } |
| |
| @override |
| void close() { |
| if (_subscription != null) _subscription.cancel(); |
| _subscription = null; |
| _eventsController.close(); |
| } |
| } |